1. Field of the Invention
The invention relates to a backlight unit and a liquid crystal display module (LCDM), and more particularly, to a backlight unit including a side support that is compactly combined with a bottom frame and an LCDM including the backlight unit.
2. Discussion of the Related Art
As the society has entered in earnest upon an information age, a field of display devices that represent all sorts of electrical signals as visual images has developed rapidly and many kinds of flat panel display devices (FPDs), such as liquid crystal display (LCD) devices, plasma display panels (PDPs), field emission display (FED) devices, electroluminescence display (ELD) devices, and so on, have been introduced. Since they have excellent capabilities of a thin profile, light weight and low power consumption, and so on, they are substituted for the cathode ray tube (CRT) rapidly and came into the spotlight.
Among these devices, LCD devices are widely used for notebook computers, monitors, TV, and so on, because of their high contrast ratio and characteristics adequate to display moving images. Generally, an additional light source is required because the LCD panel is a non-emissive-type display device. Accordingly, a backlight unit is disposed under the LCD panel. The LCD device displays images using light produced by the backlight unit and supplied to the LCD panel.
The backlight unit may be divided into an-edge type and a direct type depending on arrangement of light source. In the edge type backlight unit, one light source is positioned at a side of the backlight unit. Particularly, the light source is positioned at a side of a light guide plate of the backlight unit. Or, a pair of light sources is positioned at both side of the light guide plate. In the edge type backlight unit, there is an advantage of a simple fabricating process, while it is not available for a large size LCDM.
In the direct type backlight unit, at least one light source is positioned under an optical sheet. There is an advantage of application for a large size LCDM due to uniform light in the direct type backlight unit.
FIG. 1 is a cross-sectional view of a related art direct type liquid crystal display module (LCDM). Referring to FIG. 1, the LCDM includes a liquid crystal panel 10, a backlight unit 20, a main frame 30 and a top frame 40. The liquid crystal panel 10 includes first and second substrates 12 and 14 facing each other and a liquid crystal layer therebetween. The liquid crystal panel 10 is connected to gate and data printed circuit boards (PCBs) (not shown) through a flexible circuit board (not shown) that provide a scanning signal and an image signal to the liquid crystal panel 10, respectively.
The backlight unit 20 includes a bottom frame 50, a reflective sheet 22, a lamp 24, an optical sheet 26 and a side support 28. The reflective sheet 22 is disposed on the bottom frame 50, and the lamp 24 is arranged on the reflective sheet 22. The side support 28 is disposed at both ends of the lamp 24 to fix the lamp 24. The optical sheet 26 is disposed over the lamp 24 and the side support 26 and includes at least one diffusion plate (not shown) and a prism sheet (not shown).
The backlight unit 20 is disposed at a backside of the liquid crystal panel 10. The liquid crystal display panel 10 and the backlight unit 20 are combined using the main frame 30 that can prevent movement of the liquid crystal panel 10 and the backlight unit 20. The top frame 40 cover edges of the liquid crystal panel 10 and sides of the main frame 30, so the top frame 40 can support and protect of the edges of the liquid crystal panel 10 and sides of the main frame 30. The bottom frame 50 covers back edges of the main frame 30, so the bottom frame 50 is combined with the main frame 30 and the top frame 40 for modulation.
The side support 28 is combined with the bottom frame 50 using at least two fixing elements. It is explained with reference to FIG. 2.
FIG. 2 is a cross-sectional view showing a combined structure of a side support and a bottom frame according to the related art. Referring to FIG. 2, the side support 28 includes first to fourth side surfaces 28a, 28b, 28c and 28d and is disposed at a side of a reflective sheet 22. The first and second side surfaces 28a and 28b, and the third and fourth side surfaces 28c and 28d face each other, respectively. The first side surface 28a adjacent to a lamp 24 is oblique to the reflective sheet 22. The second side surface 28a is substantially perpendicular to the reflective sheet 22, and the third and fourth side surfaces 28c and 28d are substantially parallel to the reflective sheet 22. The side support 28 is combined with the bottom frame 50 and includes an opening (not shown) where an end of the lamp 24 is inserted.
In addition, the side support 28 includes a protrusion 29a protruding from the second side surface 28b and a first screw hole (not shown) at the fourth side surface 28d. The bottom frame 50 includes a bottom surface 50a, a first side wall 50b and second, third and fourth side walls (not shown). The first side wall 50b includes a hole 51. The hole 51 is at the first side wall 50a and corresponds to the hook 29a. By the protrusion 29a is inserted into the hole 51, the side support 28 is combined with the bottom frame 50. Moreover, the bottom frame 50 includes a second screw hole (not shown). The second screw hole (not shown) is disposed at the bottom surface 50a of the bottom frame 50 and corresponds to the first screw hole (not shown) of the side support 28. By inserting a screw 29b into the first and second screw holes (not shown), the side support 28 is further combined with the bottom frame 50.
However, there are some problems. Production costs and production time increase because of the screw 29b. Moreover, particles are generated when the screw 29b is inserted into the first and second-screw holes (not shown). There are damages on the side support 28 by stress from a process of inserting the screw 29b into the first and second screw holes (not shown). Moreover, particles are generated when the screw 29b is inserted into the first and second screw holes (not shown). The particles may degrade properties of a driving circuit (not shown). In addition, the particles affect the liquid crystal panel 10 (of FIG. 1) such that image qualities are degraded.